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A reaction at 1 bar is non–spontaneous at low temperature but becomes spontaneous at high temperature. Identify the correct statement about the reaction among the following:
  • a)
    ∆H is negative while ∆S is positive.
  • b)
    Both ∆H and ∆S are negative.
  • c)
    ∆H is positive while ∆S is negative.
  • d)
    Both ∆H and ∆S are positive.
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
A reaction at 1 bar is non–spontaneous at low temperature but becomes...
Explanation:

The spontaneity of a reaction is determined by the change in Gibbs free energy (ΔG) which is given by the equation:

ΔG = ΔH - TΔS

Where:
ΔG = Gibbs free energy change
ΔH = Enthalpy change
T = Temperature in Kelvin
ΔS = Entropy change

If ΔG is negative, the reaction is spontaneous. If ΔG is positive, the reaction is non-spontaneous.

In this case, the statement says that the reaction is non-spontaneous at low temperature but becomes spontaneous at high temperature. This means that at low temperature, ΔG is positive but at high temperature, ΔG becomes negative.

To determine the sign of ΔG, we need to consider the signs of ΔH and ΔS.

ΔH and ΔS:
- ΔH represents the change in enthalpy, which is the heat energy absorbed or released during a reaction. If ΔH is negative, it means that the reaction releases heat and is exothermic. If ΔH is positive, it means that the reaction absorbs heat and is endothermic.
- ΔS represents the change in entropy, which is a measure of the randomness or disorder of a system. If ΔS is positive, it means that the reaction increases the randomness of the system. If ΔS is negative, it means that the reaction decreases the randomness of the system.

Analysis:
- At low temperature, the reaction is non-spontaneous, which means that ΔG is positive. To make ΔG positive, either ΔH must be positive or TΔS must be negative.
- At high temperature, the reaction becomes spontaneous, which means that ΔG is negative. To make ΔG negative, either ΔH must be negative or TΔS must be positive.

Conclusion:
Since the reaction becomes spontaneous at high temperature, it means that TΔS is positive. Therefore, the correct statement is that both ΔH and ΔS are positive (option D). This means that the reaction is endothermic (ΔH > 0) and increases the randomness of the system (ΔS > 0) at high temperature.
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Community Answer
A reaction at 1 bar is non–spontaneous at low temperature but becomes...
∆G = ∆H-T∆S
For a spontaneous reaction ∆G = -ve
which is possible when both ∆H and ∆S are positive at high temperature and hence the reaction becomes spontaneous.
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Read the passage given below and answer the following questions:The rate of a reaction, which may also be called its velocity or speed, can be defined with relation to the concentration of any of the reacting substances, or to that of any product of the reaction. If the species chosen is a reactant which has a concentration c at time t the rate is - dc/dt, while the rate with reference to a product having a concentration x at time t is dx/dt. Any concentration units may be used for expressing the rate; thus, if moles per liter are employed for concentration and seconds for the time, the units for the rate are moles litre–1sec–1. For gas reactions pressure units are sometimes used in place of concentrations, so that legitimate units for the rate would be (mm. Hg) sec–1 and atm. sec–1 The order of a reaction concerns the dependence of the rate upon the concentrations of reacting substances; thus, if the rate is found experimentally to be proportional to the ath power of the concentration of one of the reactants A, to the both power of the concentration of a second reactant B, and so forth, via., rate = k CAα CAβ the over-all order of the reaction is simply n = α + β + ----- (2) Such a reaction is said to be of the αth order with respect to the substance A, the βth order with respect to B.In the following questions, a statement of Assertion followed by a statement of Reason is given. Choose the correct answer out of the following choices on the basis of the above passage.Assertion: The unit of k is independent of order of reaction.Reason: The unit of k is moles L–1s–1.

Read the passage given below and answer the following questions:The rate of a reaction, which may also be called its velocity or speed, can be defined with relation to the concentration of any of the reacting substances, or to that of any product of the reaction. If the species chosen is a reactant which has a concentration c at time t the rate is - dc/dt, while the rate with reference to a product having a concentration x at time t is dx/dt. Any concentration units may be used for expressing the rate; thus, if moles per liter are employed for concentration and seconds for the time, the units for the rate are moles litre–1sec–1. For gas reactions pressure units are sometimes used in place of concentrations, so that legitimate units for the rate would be (mm. Hg) sec–1 and atm. sec–1 The order of a reaction concerns the dependence of the rate upon the concentrations of reacting substances; thus, if the rate is found experimentally to be proportional to the ath power of the concentration of one of the reactants A, to the both power of the concentration of a second reactant B, and so forth, via., rate = k CAα CAβ the over-all order of the reaction is simply n = α + β + ----- (2) Such a reaction is said to be of the αth order with respect to the substance A, the βth order with respect to B.In the following questions, a statement of Assertion followed by a statement of Reason is given. Choose the correct answer out of the following choices on the basis of the above passage.Assertion: Rate of reaction is a measure of change in concentration of reactant with respect to time.Reason: Rate of reaction is a measure of change in concentration of product with respect to time.

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A reaction at 1 bar is non–spontaneous at low temperature but becomes spontaneous at high temperature. Identify the correct statement about the reaction among the following:a)∆H is negative while ∆S is positive.b)Both ∆H and ∆S are negative.c)∆H is positive while ∆S is negative.d)Both ∆H and ∆S are positive.Correct answer is option 'D'. Can you explain this answer?
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A reaction at 1 bar is non–spontaneous at low temperature but becomes spontaneous at high temperature. Identify the correct statement about the reaction among the following:a)∆H is negative while ∆S is positive.b)Both ∆H and ∆S are negative.c)∆H is positive while ∆S is negative.d)Both ∆H and ∆S are positive.Correct answer is option 'D'. Can you explain this answer? for NEET 2024 is part of NEET preparation. The Question and answers have been prepared according to the NEET exam syllabus. Information about A reaction at 1 bar is non–spontaneous at low temperature but becomes spontaneous at high temperature. Identify the correct statement about the reaction among the following:a)∆H is negative while ∆S is positive.b)Both ∆H and ∆S are negative.c)∆H is positive while ∆S is negative.d)Both ∆H and ∆S are positive.Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for NEET 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A reaction at 1 bar is non–spontaneous at low temperature but becomes spontaneous at high temperature. Identify the correct statement about the reaction among the following:a)∆H is negative while ∆S is positive.b)Both ∆H and ∆S are negative.c)∆H is positive while ∆S is negative.d)Both ∆H and ∆S are positive.Correct answer is option 'D'. Can you explain this answer?.
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